Clutch



Aug. Z2, 1933. w, J, PEARMAIN 1,923,453

CLUTCH Filed sept. 29, 1930 Patented Aug. 22, 1933 sie .oLU'ron fi. Eearrnain, Racine, Wis., assigner to` Clutch Company, Racine, l .ion of Wisconsin Application September 29, 1930 Serial No. 485,150

`3 Claims. k(Cl. lS2--76) My invention relates, to expanding clutches c which friction shoes are mounted upon one of the parts which it is interded to lock agaii'ist relative rotation and, by su means, spread out ward against an internal cylindrical or conical. surface with which the friction shoes niake frictional Contact. Itis the ob t of iny invention to provide a clutch of this cl which is cient in operation, durabi e ensive to uranufacture and may be read enibled, lusofar as is necessary to effect repairs due to etc.

In the drawing acconlparigdne` .and forming a part of this application, Fie. l is an elevation of a clutch embodying my invention, partly broken section on a plan'eperaway and partly show! pendicuiar to the axis Fig. 2 is a fragnieii scale, parts being sbo n in axial section.

In the form of inve on chosen for exemplification thereof and shown in 'the drawing, 3 is a shaft on which the oper ng element of the lclutch is mounted, an Al the rini lof a ilywheel or4 the like with the inver periphery oi which the shoes engage when i desired to lock the shaft to the inernber ll.

The spider or frame .1i

tnereor, and Vry top plan on asmaller f clutch may be of cast metal and coi.. -a number of radial guides, shown at 6, .ich the friction shoes are guided. Each guide comprises ya pair of guide posts or members 6', the inner and side walls of which are generallyrparallel and preferably machinedj The frame or spider isfurther cut away intermediate the guide posts of Fig. 2 to form a relatively narrow neck to receive the elongated portieri of the sleeve 9 to be presently described and below neck portion is undercut at 7 to receive the head l0 of said sleeve and to form shoulders 7 which extend over the head when the latter is in position and substantially prevent longitudinal movement of the sleeve. The sleeve 9, above mentioned, is inter nally threaded for a'purpose which will presently appear and is of an external diameter to closely fit within the neck of the spider, previously mentioned. The head l0 or the sleeve extends into and closely nts the undercut extensions or pockets in the spider, referred to above. In assembling the sleeve 9 with the spider it is slid axially of the clutch into the neck and recess of `the spider previously mentioned and is'held in place therein by straps 1l bolted at l2 to the spider on opposite sides of the latter. The sleeve 9 is flattened on opposite sides Where it is enniore Yspeciiically stated, the well-known type in gaged by the straps so that the latter hold't from turning. A simi nut or internally threaded sleeve 13 is mounted on each shoe, as will be presently explained. Double screw shafts 14, the threads on pectlve opposite ends of which are reversely inclined, engage the respective nuts so that the turning of the shaft in one direction causes the nuts to move apart and, turning the screw shaft in the other direction causes the nuts to approach each other. The nuts 9, however, being held against axial movenient, the turning or rotation of thescrew shafts afects only the nuts 13. f

Each-shoe is formedy ofrtwo sections, which may be readily assembled and disassembled, an

outer section 15, and an inner section 16. The v place and outwardly extending lugs 19 which are bolted at 20 to the respective opposite sides of the guide members 1'? and extend overV the guide posts 6 to embrace the latter and hold the friction shoe in place but permit it to slide radially of the clutch. It will now be evident that as the doublethreaded screw-shaft is rotated in one direction it will move inwardly or outwardly, as the case may be, in the nut 9 and the nut 13 will similarly move on the outer end of the shaft but will have double the motion of the screw shaft.

The outer face of the inner member 16 of the shoe is or may be concentric with the clutch and is f provided with keys 20 let into recesses therein and projecting above said surface. The outer member 15 of the shoe is or may be provided with la facing 21 of friction material and the inner surface thereof is formedv to iit the outer surface of the inner member 16, being provided also with grooves to receive the keys 20. The outer member 15 of the shoe is likewise provided with inwardly projecting'ears 22 which lap over theinner member 16 of the shoe and are bolted to the latter at 23. Thus when it is necessary to reface the shoe with friction material or repair the latter, the bolts 23 may be Withdrawn and the outer shoe section slid out parallel 'to the axis of the clutch, the other parts of the clutch remaining in place. When it is desired to repair or replace parts of the mechanism for expanding and retractingrthe series of friction shoes, the nuts and double screw shafts or any of them may be vremoved vas units by unbolting and removing the' straps 11 and 18 and moving the parts axially of the clutch.

Intermediate the nuts 9, 13, the doubly threaded shaft is formed with an enlargement 24, the outer surface of which may be substantially circular and serrated, and an operating lever 25 is secured to the shaft, being formed for this purpose with a split collar 26 which is internally serrated to correspond to the serration on the enlarged part of the shaft over which it ts. A bolt 27 extends through the end yof the split collarand normally holds the latter` tight about the enlargement of the'shaft. It may be adjusted With reference to the shaft, however, by relieving the pressure of the bolt and may then be turned about the shaft and when the proper adjustment is secured the bolt 27 may again be tightened. Preferably, means are provided for lubricating the doublythreaded shaft in its bearings. For thisepurpose I haveshown felt washers 28 and 29 located Within .the bores of the respective nuts at the respective opposite ends of the shaft, and other felt washers 39 which are held against the adjacent ends of the respective nuts by means of cups 31.

Any suitable means may beV employed for operating the levers 25. Forthis purpose, as best seen in Fig. 2, in the exemplary construction, I havey employed a ring 33 shiftable along the shaft 3 and connected by links 34 to the outer ends of the respective levers 25. Preferably, the links are connected either to the levers or to the ring by uni- `versal joints of any ordinary or usual character,

by which the clutch is operated may be provided as usual withv trunnions 38 for engagement with the shifting lever. f

I claim:

l.' In a clutch of the class described including a r`friction shoe, a spider, radial guides thereon, each comprising a pair of parallel guide posts, an in'- ternally threaded ksleeve secured between said` guide posts, a second internally threaded sleeve secured to the friction shoe in axial alignment with the first said sleeve, a screw. shaft the threads at the respective ends of which are reversely pitched, a lever secured to said shaft intermediate its threaded ends, and means for operating the lever, and detachable means for securing each of said sleeves in their operative position and, upon detachment, permitting of removal of said sleeves and'shaft as a unit by movement of the saine in axial direction.

2. In a clutch of the class described, a spider vhaving radial guides thereon each guide formed off'parallel guide posts, a friction shoe for each guide having a tongue extending between the guide posts thereof, an internally threaded sleeve secured to each shoe, a second internally threaded sleeve secured between the posts of each guide in alignment with the internally threaded sleeve on the shoe, a pair of straps secured to the tongue of each said shoe on opposite sides thereof, embracing the said internally threaded sleeve of the shoe and extending partially over the guide posts, an voperating shaft the threads on thefinner end of Which cooperate with the sleeve on the spider and the threads on the outer end of which cooperate with the sleeve on the shoe, means detachable for removal of said second sleeve with said rst sleeve and for holding said second sleeve against rotation, a lever connected to the shaft intermediate the threaded sleeves, and means for swinging thelever.

3. In a clutch of the class described, a spider having radial guides thereon in pairs and an undercut recess intermediate the vguides of each pair, an internallythreaded sleeve having an enlarged head received in said recess, means for securing the sleeve Within the recess but permitting itsV removal axially of the clutch, a friction shoe for each pair of guides having a tongue extending between the same, the tongue being formed With an undercut recess, an internally threaded sleeve havingan enlarged head received in said tongue and removable therefrom axially of the clutch, means for retaining the last-mentioned sleeve in position in the tongue of the shoe, an operating shaft, the ends of which are reversely threaded and engage the respective sleeves, and a lever connected to the shaft inter- Vmediate its threaded ends and means for swinging the lever. e Y WILLIAM J. PEARMAIN. 

